import React, { Component } from 'react'
import './index.css'
export default class Footer extends Component {
    //全选CheckBox的回调
    handleCheckAll=(event)=>{
         this.props.checkAllTodo(event.target.checked)
    }
    //清除已完成的回调
    handleClearAllDone=()=>{
        this.props.clearAllDone()
    }
    render() {
        //获取值
        const {todos} =this.props
        //计算已完成的个数
        const donCount = todos.reduce((pre,todo)=>pre + (todo.done?1:0),0)
        //总数
        const total = todos.length
        
        return (
            <div className="todo-footer">
                <label>
                    <input type="checkbox" onChange={this.handleCheckAll} checked={donCount===total && total!==0 ? true:false}/>
                </label>
                <span>
                    <span>已完成{donCount}</span> / 全部{total}
                </span>
                <button onClick={this.handleClearAllDone} className="btn btn-danger">清除已完成任务</button>
            </div>
        )
    }
}
